Decanting a mature wine promotes the separation of sediments and wine. Decanting a young wine allows it to open up and reveal more complexity, aromas and flavors.
It is possible to have it restored almost to new condition, by means of acid cleaning. The large crystal factories (Saint-Louis, Baccarat, etc.) no longer have, to our knowledge, an in-house service to repair a damaged piece. There are not very many of them anymore: Schweitzer and Cristal Benito crystal factories in Paris.